Two seam bowlers with a combined age of 66 restricted New Zealand to just 198 to set up a comprehensive seven-wicket victory for Australia at The Oval.

Glenn McGrath and Michael Kasprowicz both took three wickets on a blameless track and on a sunny day.

Ricky Ponting's side were able to bowl first after winning the toss, and New Zealand had to rebuild gingerly after crashing to 89-7 in the 24th over.

Damien Martyn and Andrew Symonds saw Australia home in the 38th over.

They each scored unbeaten half-centuries after Matthew Hayden had got the ball rolling with seven boundaries and one six in his innings of 47.

And although Adam Gilchrist fell in the first over, bowled as he played no shot to Jacob Oram, there was little cause for alarm, despite Ricky Ponting also failing when he was bowled through the gate by Scott Styris.

Martyn gave a masterclass in cutting and sweeping as he finished on 60 while Symonds's innings was more cavalier - four sixes came off his bat in a score of 71 off just 47 balls, the pair putting on exactly 100 in less than 14 overs at the end.

Australia have now booked a semi-final date against either England or Sri Lanka while New Zealand are on the plane home.

For the first half-hour of play, however, it looked like the Kiwis might reap the benefit of setting a target as Stephen Fleming and Nathan Astle played some confident shots to get the scoreboard moving.

Hayden got the Australia reply going in no-nonsense fashion

But McGrath, who had been hit for four boundaries by Astle, got the last ball of his fourth over to seam in a little and rejoiced when umpire Steve Bucknor gave the batsman out.

Hamish Marshall was soon out for a duck, departing in similar fashion although replays showed the ball might have cleared the stumps.

There was nothing uncertain about the departure of Styris, however. The pressure told as he steered his 11th ball straight to gully having failed to get off the mark, and McGrath had three out of three.

Ricky Ponting then replaced Jason Gillespie with Kasprowicz at the other end and the rewards were instant.

Fleming was caught at mid-on as a pull shot went dreadfully wrong and after a brief respite and the addition of 30 runs from 49-4, three more wickets fell in a heap.

Oram drove a return catch to Kasprowicz and Chris Cairns was lbw to the same bowler for a golden duck - although umpire Rudi Koertzen got this one wrong, the ball striking Cairns high on the pad and looking to be clearing the stumps by several inches.

To cap it all, Craig McMillan was then run out after an appalling mix-up with Chris Harris.

Just as it seemed New Zealand would struggle to reach 100, Brendon McCullum produced one of his best efforts in one-day cricket, hitting 47 at number nine, given some support from Harris and Daniel Vettori.

But in their heart of hearts, the Kiwis knew that any score below 250 would be difficult to defend.